What is epiglottis

The epiglottis is a leaf-shaped elastic cartilage flap behind your tongue (epiglottis means “upon the tongue”), which bends down to cover the glottis (opening) of the larynx each time you swallow. The epiglottis is a flap of elastic cartilage that sits beneath the tongue at the back of the throat. Its main function is to close over the windpipe (trachea) while you’re eating, to prevent food entering your airways. The epiglottis stalk attaches anteriorly to the internal aspect of the angle of the thyroid cartilage (Figure 1). From there, the epiglottis projects superoposteriorly and attaches to the posterior aspect of the tongue.

Figure 1. Epiglottis anatomy

Where is the epiglottis located

The epiglottis is located behind your tongue and it sits beneath the tongue at the back of the throat.

Figure 2. Epiglottis location

Figure 3. Epiglottis function

Epiglottis function

During swallowing, the entire larynx is pulled superiorly and anteriorly by the suprahyoid muscles, and the epiglottis tips inferiorly to cover and seal the laryngeal inlet. This action keeps food out of the lower respiratory tubes — so that food is not inhaled into your lungs. The entry into the larynx of anything other than air initiates the cough reflex, which expels the substance and prevents it from continuing into the lungs. By pulling anteriorly on the hyoid bone, suprahyoid muscles also widen the pharynx to receive the food.

The taste receptors occur in taste buds in the mucosa of the mouth and pharynx. The majority of the 10,000 or so taste buds are on the surface of the tongue; a few others occur on the epiglottis. The vagus nerve (cranial nerve 10) carries taste impulses from the few taste buds on the epiglottis and lower pharynx.

Epiglottitis

Epiglottitis is a potentially life-threatening inflammation and swelling of the epiglottis with the potential risk of fatal airway obstruction – blocking the flow of air into your lungs (see Figures 1 and 2) ¹⁾. Acute epiglottitis is known to be potentially life-threatening because the special structure and anatomical location of the epiglottis (see Figures 1 and 2) make it prone to severe edema, which can lead to dyspnea and even suffocation, resulting in death ²⁾. In most cases, epiglottitis is caused by infection. Effective management requires rapid diagnosis, airway management, and treatment of the causative agent.

The epiglottis is a flap of tissue that sits beneath the tongue at the back of the throat. Its main function is to close over the windpipe (trachea) while you’re eating, to prevent food entering your airways.

Acute epiglottitis can occur at any age. Epidemiological studies have shown that the number of acute epiglottitis cases has decreased in children due to proper vaccinations, while the number of adult cases has increased significantly ³⁾. Previously, 75%–90% of cases of epiglottitis were caused by Haemophilus influenza type B (Hib), the same bacterium that causes pneumonia, meningitis and infections in the bloodstream. Haemophilus influenzae type b (Hib) bacteria spreads in the same way as the cold or flu virus; the bacteria are in the tiny droplets of saliva and mucus propelled into the air when an infected person coughs or sneezes. You catch the infection by breathing in these droplets or, if the droplets have landed on a surface or object, by touching this surface and then touching your face or mouth. Because of the success of the Hib vaccination programme, epiglottitis is rare in the US, and most cases now occur in adults. Deaths from epiglottitis are also rare, occurring in less than 1 in 100 cases. But infection with group A beta-hemolytic Streptococci has become more frequent after the widespread use of Hemophilus influenzae type B (Hib) vaccination. Hib vaccination, introduced in 1985, significantly reduced the incidence of epiglottitis ⁴⁾. Routine Hemophilus influenzae type B (Hib) vaccination for infants has made epiglottitis rare, but epiglottitis remains a concern. Cases presenting today show a mixed microbial etiology (other bacteria as well as fungi and virus), with a relative increased incidence in older children ⁵⁾. A number of other factors can cause the epiglottis to swell — burns from hot liquids, direct injury to your throat and various infections.

Less common causes of acute epiglottitis include:

• other bacterial infections – such as streptococcus pneumoniae (a common cause of pneumonia)
• fungal infections – people with a weakened immune system are most at risk from these types of infection
• viral infections – such as the varicella zoster virus (the virus responsible for chickenpox) and the herpes simplex virus (the virus responsible for cold sores)
• trauma to the throat – such as a blow to the throat, or burning the throat by drinking very hot liquids
• smoking – particularly illegal drugs, such as cannabis or crack cocaine

The clinical features of acute epiglottitis commonly include sore throat, odynophagia [painful swallowing], stridor [high-pitched, wheezing sound caused by obstructed airflow], fever, hoarseness, drooling, hyperpyrexia, and dyspnea [difficult or labored breathing or shortness of breath] ⁶⁾.

The typical histopathological changes associated with this condition include extensive mucosal or submucosal edema accompanied by neutrophil infiltration and hemorrhage, which are frequently found microscopically. In addition, epiglottic abscess may be observed in some patients with acute epiglottitis (approximately 24% of the cases) ⁷⁾.

There are differences in trends, occurrences and management of acute epiglottitis between children and adults. There is also more diversity in the cause of epiglottitis in adults ⁸⁾.

In an 8-year retrospective (1998–2006) review of epiglottitis admissions, Shah et al. ⁹⁾ found that epiglottitis continues to be a significant entity, with two uniquely vulnerable populations: infants (<1 year old) and the elderly (>85 years old). When examining the pediatric cohort of patients (patients <18 years of age), 34.4% were <1 year of age. This category of age <1 year seemed to have increased in frequency in representing 26.8% of pediatric patients in 1998 to 41.1% in 2006 ¹⁰⁾. A case of epiglottitis with negative cultures has been reported in a neonate within hours of birth ¹¹⁾.

Croup vs epiglottitis

Croup is a viral laryngotracheobronchitis (usually caused by the Hemophilus parainfluenzae virus) that causes swelling of the windpipe (trachea), the airways to the lungs (the bronchi) and the vocal cords (larynx or voice box). This swelling makes the airway narrower, so it is harder to breathe. Croup causes difficulty breathing, a seal barking cough, and a hoarse voice. The cause is usually a virus, often parainfluenza virus. Other causes include allergies and reflux. Treatment of croup includes oxygen, steroids (dexamethasone 0.6 mg/kg PO/IM) and epinephrine (to relieve airway edema and decrease airway resistance due to swelling).

Epiglottitis is an inflammation of the epiglottis due to an infectious process. It can involve other structures such as the arytenoid, false cords and posterior tongue leading to airway obstruction. Most often epiglottitis is bacterial in origin due to Hemophilus influenzae type B (Hib), it affects children between 2 and 5, however the median age is increasing over the past decade. It presents acutely in otherwise healthy children with a fever as high as 104 °F (40 °C). Epiglottic inflammation occurs quickly with the child sitting forward to use the accessory muscles of respiration and pain in the throat. Salivation is prominent with difficulty swallowing. Treatment includes keeping a parent in attendance at all times to keep the child calm, oxygen, sitting position, immediate intubation. Diagnosis is confirmed through radiologic studies showing the steeple sign representing a uniform narrowing of the subglottic airway by inflammation.

Croup is more prevalent during the wintertime, while there is no seasonal predilection to epiglottitis. Croup also has a more gradual onset than acute epiglottitis, and is commonly associated with low-grade fever. Although both acute epiglottitis and croup share the same symptoms of inspiratory stridor, suprasternal, intercostal and substernal retractions and hoarseness, differentiation in early illness is possible by additional observation of seal barking cough and absence of drooling and dysphagia in croup and by the additional observation of drooling and dysphagia with absence of coughing in epiglottitis. Additional reliable signs of epiglottitis are a preference to sit, dysphagia and refusal to swallow ¹²⁾. Unlike croup, where onset is insidious over a period of 2 to 3 days, epiglottitis patients tend to experience acute onset of symptoms. In one series, while both croup and epiglottitis were associated with acute stridor, croup was also associated with coughing and no drooling, while epiglottitis was associated with drooling and the lack of coughing ¹³⁾.

Epiglottitis causes

Epiglottitis is usually caused by epiglottis infection with Haemophilus influenzae type b (Hib) bacteria.

As well as epiglottitis, Haemophilus influenzae type b (Hib) can cause a number of serious infections, such as pneumonia and meningitis.

Haemophilus influenzae type b (Hib) spreads in the same way as the cold or flu virus. The Haemophilus influenzae type b (Hib) bacteria are in the tiny droplets of saliva and mucus propelled into the air when an infected person coughs or sneezes.

You catch Haemophilus influenzae type b (Hib) infection by breathing in these droplets or, if the droplets have landed on a surface or object, by touching this surface and then touching your face or mouth.

Less common causes of epiglottitis include:

• other bacterial infections – such as streptococcus pneumoniae (a common cause of pneumonia)
• fungal infections – people with a weakened immune system are most at risk from these types of infection
• viral infections – such as the varicella zoster virus (the virus responsible for chickenpox) and the herpes simplex virus (the virus responsible for cold sores)
• trauma to the throat – such as a blow to the throat, or burning the throat by drinking very hot liquids
• smoking – particularly illegal drugs, such as cannabis or crack cocaine

Haemophilus influenzae type b (Hib) vaccination

The most effective way to prevent your child getting epiglottitis is to make sure their vaccinations are up-to-date.

Children are particularly vulnerable to a Haemophilus influenzae type b (Hib) infection because they have an underdeveloped immune system.

Risk factors for epiglottitis

Certain factors increase the risk of developing epiglottitis, including:

• Being male. Epiglottitis affects more males than females.
• Having a weakened immune system. If your immune system has been weakened by illness or medication, you’re more susceptible to the bacterial infections that may cause epiglottitis.
• Lacking adequate vaccination. Delayed or skipped immunizations can leave a child vulnerable to Hib and increases the risk of epiglottitis.

Figure 3. Swollen epiglottis

Epiglottitis prevention

Haemophilus influenzae type b (Hib) vaccine

The most effective way to prevent your child getting epiglottitis is to make sure their vaccinations are up to date.

Children are particularly vulnerable to a Haemophilus influenzae type b (Hib) infection, because they have an underdeveloped immune system.

Children should receive their Haemophilus influenzae type b (Hib) as part of the 5 in 1 DTaP/IPV/Hib vaccine, which also protects against diphtheria, tetanus, whooping cough and polio.

Immunization with the Haemophilus influenzae type b (Hib) vaccine is an effective way to prevent epiglottitis caused by Haemophilus influenzae type b (Hib). Children should receive three doses of the vaccine: one at two months, one when they are three months and one when they are four months old. This is followed by an additional Hib/Men C “booster” vaccine at 12 months.

In the United States, children usually receive the vaccine in three or four doses:

• At 2 months
• At 4 months
• At 6 months if your child is being given the four-dose vaccine
• At 12 to 15 months

The Haemophilus influenzae type b (Hib) vaccine is generally not given to children older than age 5 or to adults because they’re less likely to develop Hib infection. But the Centers for Disease Control and Prevention recommends the vaccine for older children and adults whose immune systems have been weakened by:

• Sickle cell disease
• HIV/AIDS
• Spleen removal
• Chemotherapy
• Medications to prevent rejection of organ or bone marrow transplants

Haemophilus influenzae type b (Hib) vaccine side effects

• Allergic reaction. Seek immediate medical help if you have an allergic reaction. Though rare, an allergic reaction may cause difficulty breathing, wheezing, hives, weakness, a rapid heartbeat or dizziness within minutes or a few hours after the shot.
• Possible mild side effects. These include redness, warmth, swelling or pain at the injection site, and a fever.

Commonsense precautions

Of course, the Hib vaccine doesn’t offer guarantees. Immunized children have been known to develop epiglottitis — and other germs can cause epiglottitis, too. That’s where commonsense precautions come in:

• Don’t share personal items.
• Wash your hands frequently.
• Use an alcohol-based hand sanitizer if soap and water aren’t available.

Symptoms of epiglottitis

The symptoms of epiglottitis usually develop quickly and get rapidly worse, although they can develop over a few days in older children and adults.

The typical presentation in epiglottitis includes acute occurrence of high fever, severe sore throat and difficulty in swallowing with the sitting up and leaning forward position in order to enhance airflow. There is usually drooling because of difficulty and pain on swallowing. Acute epiglottitis usually leads to generalized toxemia. The most common differential diagnosis is croup and a foreign body in the airway. A late referral to an acute care setting with its serious consequences may result from difficulty in differentiation between acute epiglottitis and less urgent causes of a sore throat, shortness of breath and dysphagia. Antibiotic therapy is usually initiated without preceding bacterial culture, with the consequence of negative cultures at admission.

Epiglottitis symptoms include:

• a severe sore throat
• difficulty and pain when swallowing
• difficulty breathing, which may improve when leaning forwards
• breathing that sounds abnormal and high-pitched (stridor)
• a high temperature (fever) of 38 °C (100.4 °F) or above
• irritability and restlessness
• muffled or hoarse voice
• drooling

The main symptoms of epiglottitis in young children are breathing difficulties, stridor and a hoarse voice. In adults and older children, the main signs are a severe sore throat, swallowing difficulties and drooling.

Difficulty in breathing and stridor are common signs of epiglottitis in children, but are less frequent in adults. The most common presenting symptom in adults is odynophagia [painful swallowing] (100%), followed by dysphagia [difficulty in swallowing] (85%) and voice change (75%) ¹⁴⁾. In adults, stridor is regarded as a warning sign for occlusion of the upper airway. Stridor, tachycardia, tachypnea, rapid onset of symptoms and a “thumb-sign” (see Figures 3 and 4 below) present in 79% of the cases on lateral X-rays of the neck are significant predictors for imminent airway compromise with rapid clinical deterioration ¹⁵⁾.

Symptoms in children

In children, signs and symptoms of epiglottitis may develop within a matter of hours, including:

• Fever
• Severe sore throat
• Abnormal, high-pitched sound when breathing in (stridor)
• Difficult and painful swallowing
• Drooling
• Anxious, restless behavior
• Greater comfort when sitting up or leaning forward

Epiglottitis can cause a life-threatening airway emergency. Patients with epiglottitis usually present with a generalized toxemia, including high fevers, severe sore throat, and difficulty swallowing. Stridor, if present, is usually inspiratory. The patient may be sitting up and leaning forward in the sniffing position, breathing with an open mouth and a protruding tongue. The child frequently drools because of difficulty and pain on swallowing. This “tripod position” may not be present in the older child/adult presenting with epiglottitis. Findings may only include subtle signs of respiratory difficulties, such as the inability to lie flat, voice changes, and dysphagia. Epiglottitis patients tend to experience acute onset of symptoms. In one series, while both croup and epiglottitis were associated with acute stridor, croup was also associated with coughing and no drooling, while epiglottitis was associated with drooling and the lack of coughing.6

Symptoms in adults

For adults, signs and symptoms may develop more slowly, over days rather than hours. Signs and symptoms may include:

• Severe sore throat
• Fever
• A muffled or hoarse voice
• Abnormal, high-pitched sound when breathing in (stridor)
• Difficulty breathing
• Difficulty swallowing
• Drooling

Supraglottitis, or inflammation of the supraglottic larynx, seen in adults, has a different presentation than epiglottitis in children. Adults with supraglottitis have predominant symptoms of odynophagia, dysphagia, and voice changes out of proportion to pharyngeal inflammation. Childhood epiglottitis—muffled voice, drooling, dyspnea, stridor, and cough—occurs in less than 50% of adults ¹⁶⁾. Adults may also experience fever, toxic appearance, cervical lymphadenopathy, and anterior neck and chest cellulitis. Guardiani et al. ¹⁷⁾, based on a 10-yr study of 60 adults and 1 child, described odynophagia (painful swallowing) (100% of patients) as the most common symptom, followed by difficulty swallowing (85%) and voice changes (74%). The presentation of adult supraglottitis peaks at 42 to 48 yr of age, with a male predilection of 2.5:1 ¹⁸⁾. This “tripod position” may not be present in the older child/adult presenting with epiglottitis.

Epiglottitis complications

Epiglottitis can cause a number of complications, including:

• Respiratory failure. The epiglottis is a small, movable “lid” just above the larynx that prevents food and drink from entering your windpipe. But if the epiglottis becomes swollen — either from infection or from injury — the airway narrows and may become completely blocked. This can lead to respiratory failure — a life-threatening condition in which the level of oxygen in the blood drops dangerously low or the level of carbon dioxide becomes excessively high.
• Spreading infection. Sometimes the bacteria that cause epiglottitis cause infections elsewhere in the body, such as pneumonia, meningitis or a blood infection (sepsis).

Epiglottitis can lead to airway loss and death. Epiglottic abscess has been found to occur in up to 24% of patients ¹⁹⁾. The abscesses can often be detected using a computed tomography scan, while a magnetic resonance imaging shows obliteration of the surrounding fat planes. These scans require the patient to be in a supine position, and with this condition, respiratory distress can be greater when the patient is supine. If computed tomography or magnetic resonance imaging is felt to be necessary in a complicated patient, consideration should be given to securing the airway before placing these patients in the supine position in an imaging department. Likewise, naso-fiberoptic exam can also assess edema and abscesses even when performed on an intubated patient. Patients with epiglottic abscess often require drainage of the abscess in addition to intravenous antibiotics. Descending necrotizing mediastinitis has also been reported in cases of epiglottitis ²⁰⁾. These patients often require drainage of the mediastinum in addition to drainage of the primary abscess and airway management via tracheotomy. Immunocompromised patients are at a higher risk of these complications, and physicians must therefore use broad-spectrum antibiotics as well as debridement, as needed.

Epiglottitis diagnosis

If your doctor suspects epiglottitis, the first priority is to ensure that your or your child’s airway is open and that enough oxygen is getting through.

Initial test

A pulse oximeter is a device that estimates blood oxygen levels. This device:

• Clips onto a finger
• Measures an estimation of the saturation of oxygen in your blood

If oxygen saturation levels drop too low, you or your child may need help breathing.

Tests after stabilizing breathing

• Throat examination. Using a flexible fiber-optic-lighted tube, the doctor may look down your or your child’s throat to see what’s causing the symptoms. A local anesthetic can help relieve any discomfort. In case of the diagnosis of epiglottitis, a fibreoptic nasal intubation or rigid bronchoscopy using an endotracheal tube with substantially reduced diameter is preferred. Because of the risk of inducing laryngeal spasm and/or total airway obstruction, examination of the pharynx and larynx should be attempted only in an area with adequate equipment and staff prepared to intervene should upper airway obstruction develop, ideally, in the operating room.
• Chest or neck X-ray. Because of the danger of sudden breathing problems, children may have X-rays taken at their bedside rather than in the radiology department — but only after the airway is protected. With epiglottitis, the X-ray may reveal what looks like a thumbprint in the neck, an indication of an enlarged epiglottis.
• Ultrasonography has been described as a way to investigate the epiglottis by visualization of the “alphabet P sign” in a longitudinal view through the thyrohyoid membrane (Figure 5) ²¹⁾.
• Throat culture and blood tests. For the culture, the epiglottis is wiped with a cotton swab and the tissue sample is checked for Hib. Blood cultures are usually taken because bacteremia — a severe bloodstream infection — may accompany epiglottitis.

In acute epiglottitis, the radiological “thumb sign” (Figures 3 and 4) is indicative of severe inflammation of the epiglottis with potential for irrevocable loss of the airway. The thumb sign in epiglottitis is a manifestation of swelling and enlarged epiglottis which is seen on lateral soft-tissue radiograph of the neck, and it suggests a diagnosis of acute infectious epiglottitis. This is the radiographic corollary of the omega sign ²²⁾.

Figure 4. Thumb sign epiglottitis (child)

Figure 5. Epiglottitis ultrasonogram – note “Alphabet P sign” formed by acoustic shadow of hyoid bone (HY), swollen epiglottis (pointed by white arrows)

Epiglottitis treatment

Epiglottitis is treated in hospital!

The first thing the medical team will do is secure the person’s airways to make sure they can breathe properly.

Securing the airways

An oxygen mask will be given to deliver highly concentrated oxygen to the person’s lungs.

If this does not work, a tube will be placed in the person’s mouth and pushed past their epiglottis into the windpipe. The tube will be connected to an oxygen supply.

In severe cases where there’s an urgent need to secure the airways, a small cut may be made in the neck at the front of the windpipe so a tube can be inserted. The tube is then connected to an oxygen supply.

This procedure is called a tracheostomy and it allows oxygen to enter the lungs while bypassing the epiglottis.

An emergency tracheostomy can be carried out using local anaesthetic or general anaesthetic.

Once the airways have been secured and the person is able to breathe unrestricted, a more comfortable and convenient way of assisting breathing may be found.

This is usually achieved by threading a tube through the nose and into the windpipe.

Fluids will be supplied through a drip into a vein until the person is able to swallow.

Once this has been achieved and the situation is thought to be safe, some tests may be carried out, such as:

• a fibreoptic laryngoscopy – a flexible tube with a camera attached to one end (laryngoscope) is used to examine the throat
• a throat swab – to test for any bacteria or viruses
• blood tests – to check the number of white blood cells (a high number indicates there may an infection) and identify any traces of bacteria or viruses in the blood
• an X-ray or a CT scan – sometimes used to check the level of swelling

Any underlying infection will be treated with a course of antibiotics.

With prompt treatment, most people recover from epiglottitis after about a week and are well enough to leave hospital after 5 to 7 days.